Temperature problems using an outdoor air flow rate

asked 2016-08-30 15:13:14 -0600

nielex gravatar image

updated 2016-08-30 15:13:46 -0600

I 'am using a HVAC air loop with a Coil:Cooling:Water obejct, an OutdoorAir:Mixer object and an a Controller:OutdoorAir object. I tried to use a outdoor air flow rate of 0,026 m3/s (=max. and min outdoorair flow rate of Controller:OutdoorAir). I also tried a second approach using the Design:Specification:OutdoorAir object. For both situations I got some temperature peaks on the supply outlet only when the outdoor air flow rate value is used. Looking through the results I could find out that on the mixed air outlet I got a temperature rise of about 5 C with 27,7 C (drybulb) and 0,0096 kg/kg moisture for the outdoor air. The return air without temperature peaks is 28 C and 0,0066 kg/ kg moisture. The mixed air mass flow rate has a value of 8,67 kg/s (7,2 m3/s) and the outdoor air flow rate has a value of 0,0308 kg/s (0,026 m3/s). Consider the facts the temperature rise for the concrete point of time seems to be something strange for me.

There are some experiences using an outdoor air flow rate?

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What's the question here? Are you trying to fix the outdoor air flow rate?

Adam Hilton gravatar image Adam Hilton  ( 2016-08-30 17:17:23 -0600 )edit

What do you mean with "Are you trying to fix the outddor air flow rate"? I have set the value of 0,026 m3/s for the min outdoorair flow rate (Controller:OutdoorAir) and for the max outdoorair flow rate (Controller:OutdoorAir). Using a value of 0 I did'nt get any temperature rises. Also using a DX system with the same conditions I didn't get any temperature rises. I have also notice that a small infiltration rate also leads to some temperature rises. So the question is, if anyone knows, what could be wrong.

nielex gravatar image nielex  ( 2016-09-02 04:39:24 -0600 )edit